1. Field of the Invention
This invention relates generally to message waiting indicators for communication systems and in particular to a message waiting indicator system for detecting and reporting message waiting conditions in a wireless communications system.
2. Background
Electronic telephone message recording devices (message machines) have become common place in households and businesses throughout the world. These devices allow a caller to leave a voice message if the call recipient is not in, or is unable or unwilling to answer the call. Early message machines were stand alone units located in the home or business. More recently, local telephone service providers (LTSP) have begun offering electronic voice mail service to their customers. Obtaining voice messaging services from a LTSP provides several advantages to a subscriber, including remote message retrieval, permanent message storage and reduced equipment maintenance. Most often, the voice mail system is located and accessed at the central office of a LTSP.
A voice mail system operates by monitoring the telephone lines that are linked or associated with a voice mail service. When one of these lines receives a call, the voice mail system monitors the line to determine if the line is not answered or if the line is in use. If the line is not answered or is in use at the time of the incoming call the voice mail system forwards the incoming call to a message recorder so that the caller may leave a message for the unavailable call recipient. A call-in password restricted message retrieval system allows a properly authenticated voice mail service subscriber to retrieve stored messages.
To notify the subscriber of messages, the subscriber""s voice mail service most often transmits a short period of stuttered dial tone when the line associated with the service initially assumes an off-hook status. If a user retrieves messages from a line not associated with the subscriber""s voice mail service, the voice mail service reveals the number of new messages, if any, to the user using recorded or synthesized voice prompts.
Traditional stutter dial tone message notification requires a voice mail subscriber to physically take the telephone off-hook and listen for the stutter dial tone to determine if new messages have arrived. This is inconvenient because the subscriber must physically go to the telephone, lift the handset and listen for stutter dial tone. Moreover, in the case of those having hearing impairments, stutter dial tone may be undetectable. In U.S. Pat. Nos. 5,825,852 and 5,327,493, both of which are hereby fully incorporated by reference herein as though set forth in full, techniques are described for detecting the stutter dial tone while the telephone is in an on-hook condition, and, in response thereto, providing a visual indication of the message waiting condition. These techniques overcome at least some of the disadvantages of the traditional stutter dial tone technique.
Visual Message Waiting Indicator (VMWI) detection, defined by a specification known as CLASS (Custom Local Area Signaling Services), is a second technique for detecting message waiting conditions. The VMWI circuitry interrogates the line from the LTSP and, upon detection of a FSK (frequency shift key) formatted message indicating a message waiting condition, activates a visual indicator, such as an LED. U.S. Pat. No. 5,825,852 provides additional details about this technique.
Dual mode systems, as described in U.S. Pat. No. 5,825,852, are also available for detecting and indicating a message waiting condition in response to on-hook stutter dial tone detection or VMWI detection.
A problem with all the foregoing systems and techniques is that they are configured for use in landline systems only, and are not applicable to wireless communication systems.
Therefore, a need exists for a voice message notification system tailored for use in a wireless communication system, such as a cordless phone system.
In accordance with the purpose of the invention as broadly described herein, there is provided a message indicator system for use in a wireless communication environment comprising a base station in communication with a mail messaging system and one or more mobile units serviced by and interfaced to the base station over a wireless interface.
According to a first embodiment, at least one of the mobile units is equipped with a message indicator, which is any human perceptible indicator capable of providing a visual, aural, tactile, olfactory, or other stimulus to a human. In one implementation, the message indicator is a flashing light-emitting diode (LED). Optionally, the base station is also equipped with a message indicator.
A message status signal detection system is provided in the base station. This system monitors for communications from a mail system indicating status, or a change in status, regarding a message waiting condition. Examples include signals indicating receipt of a new message, the presence of an unread message, and the handling of a previously unread message. The system includes dual mode detection comprising stutter dial tone detection and FSK signal monitoring.
A wireless control channel is provided between the base station and the mobile unit. In one implementation, the control channel is configured in parallel with one or more voice channels, and is capable of supporting communication of control information between the base station and the mobile unit while voice communication is underway.
The message indicator is configured with first and second states for indicating respectively the presence and absence of a message waiting condition. In one implementation, the indicator is a flashing LED having a first activated state for indicating a message-waiting condition, and a second deactivated state for indicating the absence of a message waiting condition.
When a communication from the mail system is received relating to mail message status, the system activates an indicator at the base station if such is present. In one implementation, the base station then broadcasts a message to the mobile unit advising it of the status and directing it to update its indicator to reflect, or ensure that it reflects, the proper status. In response thereto, the mobile unit, if within range, i.e. able to receive the signal, updates the status of its indicator accordingly or ensures that its indicator reflects the proper status. If the mobile unit is not within range, it is not updated with the current status. The notation xe2x80x9cwithin rangexe2x80x9d defines a relationship between the base station and the mobile unit such that they are able to communication. Examples of when a base station and a mobile unit are not within range includes but is not limited to instances when obstructions when the base or mobile are not on or powered up, block signal transmission, low or dead battery condition, electrical or magnetic interference, the mobile too far away from the base, the base is not provided with power, the antenna is not fully extended and the like.
In a second implementation, the base station monitors the control channel for receipt of a heartbeat signal indicating that the mobile unit is within range and transmitting the heartbeat. Upon receipt of the heartbeat signal, the base station communicates a message to the mobile unit over the control channel advising the mobile unit to update the indicator at the mobile unit or ensure that it reflects the correct status.
If the base station does not detect a heartbeat signal, indicating that the mobile is out of range, the base station stores the desired communication in a buffer. When the base station detects the heartbeat signal, it then retrieves the desired communication from the buffer, and transmits it to the mobile over the control channel. At that point, the mobile is instructed to activate its indicator.
When the message has been handled, the messaging system notifies the base station, and the base station, in response thereto, sends a command to the mobile unit to update its indicator accordingly. More specifically, upon receipt of a heartbeat signal from the mobile, the base station transmits a communication to the mobile unit over the control channel, advising the mobile unit to deactivate the indicator. If the base station does not detect the heartbeat signal within the prescribed time, the base station buffers the communication, and transmits it to the mobile once the heartbeat signal is detected.
In a second embodiment, each of the plurality of mobile units serviced by the base station is configured with an indicator. A messaging system indicates to the base station a message status condition intended only for selected ones of the plurality of mobile units. The base station is configured to address a communication over the control channel to the selected mobile units advising these units to update their indicators to reflect the status condition. In one implementation, messages from the base station over the control channel have address information appended thereto for indicating the selected mobile units to which the communication is intended. The mobile units are each configured to process only those communications received over the control channel that are addressed to that mobile unit, and to ignore other communications over the control channel.
In one implementation, a plurality of mail messaging systems are interfaced to the base station, each for saving messages for selected ones of the mobile units serviced by the base station. The base station, upon receipt of a communication from one of these mail messaging systems regarding a message status condition, addresses the communication only to the selected mobile units that are the intended recipients of the communication. The status condition is then reflected in the indicators for the selected mobile units, and not for the other mobile units serviced by the base station.
In a third embodiment, a base station is in communication with at least one message notification unit over a wireless interface. The message notification unit is configured to communicate with the base station over the control channel only, and is not configured to communicate with the base station over a voice channel. The message notification unit is configured with an indicator for indicating the status of a mail message condition. The base station receives from the mail messaging system a communication indicating the status, or a change in status, of a mail message condition. The base station communicates this information to the message notification unit over the control channel. In response thereto, the message notification unit places the indicator in the proper state to indicate the current message waiting status.
Message notification units have the advantages of portability and low cost of manufacture in relation to a mobile unit configured with voice communication capabilities.